The GT-PC is a VoIP mission instrument that consists of a standard PC running Compunetix’ GT user interface software. The PC connects with a CONTEX conferencing system via Ethernet, and it uses a USB push-to-talk headset. The end user can touch or click soft line keys to access up to 196 voice circuits and soft function buttons to activate advanced functions such as conference focus, conference broadcast, and conference join. The PC does not need to be dedicated strictly for use as a mission instrument; it can run other applications such as the CONTEX system administration and maintenance client at the same time.